THE WONDERS OF THE HEAVENS.

Marlborough Express, Volume XLI, Issue 228, 26 September 1907, Page 7

THE WONDERS OF THE HEAVENS.

Sir David Gill, in his presidential-ad-dress at the British Association, dealt with the subject of astronomy, and * quoted authorities to prove that at one tune the Southern Cross was visible in the hemisphere. That that is no longer the case illustrates tne nature of the slow change Which astronomers with modern instruments of precision endeavour to -". register within short periods. That particular phenomenon is due to terrestrial changes which alter our point of view^, but every star in the heavens is continually changing rfcs own posi-* tion itt space as well as its apparent relation to other stars as viewed from our moving platform. The sun, with all its retinue ofplanets, is moving towards a star in Hercules, at the rate of about 12 miles per second, hence there is continual alteration in the apparent relations of the stars to one another as seen from our point of view. But besides this apparent motion there are real changes due to the proper motion of each star upon some orbit as vast as that followed by the whole solar system.To disentangle these motions, to discover how much is proper motion, bow much apparent motion due to our own change of place, and how much mere systematic error in our instruments, is the task upon which astronomers all over the world are engaged. It is a task of enormous difficulty, since we cannot independently verify j any of the data. We h&ve to measure each by a standard which is itself of unknown and perhaps unknowable value, to judge the sun's motion from the displacement of the stars, and to decompose that displacement by the conjectural value we have assigned to the motion of the sun. Astronomy in its broader aspects has always been a very popular science. It appeals to the innate love of wonder, and it fascinates by the magnitude of the quantities with which it deals. In the hands of a lecturer who can make his audience, partially realise by suitable illustrations and analogies the vastness of space, and who can confidently put forth speculations which astronomers know to be conjectural, the science appeals forcibly to a popular audience. But the real astronomical labours to which we have alluded are apt to prove too burdensome for the popular imagination, and the long chains of reasoning from data not easy to apprehend speedily weary the lay mind. The solar system is well enough when picturesquely expounded, but when the solar system becomes a mere atom travelling some 400,000,000 miles per annum towards some inconceivable goal, and when millions of similar systems have to be contemplated, all pursuing some similar course, the lay imagination is completely baffled. Nor is it easy to believe that the most eager astronomer is not sometimes perplexed and dismayed by the vistas opened up before him. For everything he learns merely opens up vaster problems, and when he has extended

his vision to stars from which light ' would take 2000 years to reach this earth, he is no nearer finality than the child who thinks the sky but a spectacle of revolving lights. We are told that the heavens as we see them are occupied by two great streams oft stars moving in opposite directions, j That suggests at least two centres of ! - revolution at some unimaginable distempfT. .a«d adds to our aching embar- I